摘要
在雷诺数处于（6.0-17.7）×10^3的条件下,利用红外热像仪测量了蒸汽冷却、不同角度V形肋通道换热表面的局部努赛尔数分布,利用计算流体动力学软件对其进行了数值模拟,分析了不同角度V形肋通道内蒸汽的传热特性及压力损失,并与相近工况下的空气冷却结果进行对比.结果表明：采用V形肋通道可以有效提高通道的强化换热特性;随着V形肋角度的减小,冷却性能不断提高,45°的V形肋通道的换热性能最佳;V形肋可使换热通道内部流体形成二次流,通道核心区的低温流体随之补充,使得通道中间靠近换热面的热边界层减薄;在相同雷诺数的条件下,蒸汽冷却的传热性能明显高于空气冷却,但两者的压力损失十分接近。
The distributions of Nusselt number （Nu） for steam cooling on V-shaped rib roughness channel with different rib angles were measured by an infrared camera for a Reynolds number （Re） range of （6.0 to 17.7） × 10^3. The results show that the heat transfer performance in the region following the upwind side of V-shaped ribs is greatly enhanced. With the rib angle decreasing, the heat transfer performance of steam cooling in the channel increases. The 45° V-shaped rib roughness channel has the best heat transfer performance in all investigated objects. The flow characteristics and pressure loss of steam flow for all investigated channels were also studied by the CFD method and compared with those of air flow in the similar op- erating conditions. It is concluded that the secondary flow in ribbed channels is induced by the V-shaped rib turbulator. The cooler flow in the core region of the channel provides a supplement to the area, which results in a thermal boundary layer thinning in that region. Therefore the heat transfer performance is en- hanced for the V-shaped rib roughness channel. In the same Reynolds number conditions, the pressure loss coefficients for steam flow and air flow are nearly the same, however, the heat transfer performance of steam flow is obviously higher than that of air flow.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2015年第5期644-650,656,共8页
Journal of Shanghai Jiaotong University
基金
国家自然科学基金项目(51206109)资助
关键词
燃气轮机
蒸汽冷却
V形肋通道
努赛尔数
摩擦因子
gas turbine
steam cooling
V-shaped ribbed channel
Nusselt number
friction factor
